Linear synchronous motor with multiple time constant circuits, a secondary synchronous stator member and improved method for mounting permanent magnets

ABSTRACT

The linear synchronous motor consists of a specific primary and secondary part. The secondary portion is a ferromagnetic back plate. An array of permanent magnets are attached to the back plate so that a fixed or variable pole pitch occurs in a precise manner between at least two magnets of alternating polarity which improves existing methods for attaching, guiding, protecting and enhancing the overall flux array produced and emitted by the permanent magnets. A one-piece electrically synchronous linear secondary stator member accompanies a primary member, the synchronous linear permanent magnet motor. The stator electrical frequency is customizeable to allow for a wide variety of braking applications.

CROSS REFERENCE

[0001] This utility application claims priority to U.S. Provisional Patent Application Serial No. 60/383,066 filed May 24, 2002 and U.S. Provisional Patent Application Serial No. 60/390,244 filed Jun. 20, 2002 (Attorney Docket Numbers 02-157 and 02-234).

FIELD OF THE INVENTION

[0002] The invention relates to linear synchronous motors, and in particular to linear synchronous motors with multiple time constant circuits and an improved method of mounting permanent magnets. An embodiment provides an electrically synchronous linear secondary stator member that accompanies a primary member, the synchronous linear permanent magnet motor. An embodiment is utilized as an electro-dynamic brake for elevators as well as amusement rides such as drop towers, roller coasters and any other mobile device that requires dependable and high thrust braking applications.

BACKGROUND OF THE INVENTION

[0003] This invention reduces or eliminates specialized tooling to attach, guide and secure into place several permanent magnets with alternating poles, situated side by side by incorporating these features into a ferromagnetic back plate and one-piece double laminated frame and cover system. In doing so, the invention eliminates the need for use of raised individual spacers, individual frame pieces and guide pins which have been utilized in previous art.

[0004] The invention improves upon existing methods of permanent magnet electro-dynamic braking. In an embodiment the system is completely synchronous. It does not operate as an eddy current induction type electrical device. The synchronous system operates differently than existing eddy current induction type brakes by directing the electrical currents into discrete circuit pathways thereby routing currents in a particular pathway along the synchronous stator. The stator electrical frequency of this system can be customized, meaning increased or decreased, for any given application, thereby allowing a variable braking force throughout the entire active braking area. This is not possible with existing solid induction type, linear stator rails made from conductive material. This allows for a wide variety of braking applications.

SUMMARY OF THE INVENTION

[0005] The invention provides a synchronous linear electrical machine operating as a motor or an electrodynamic brake consisting of an array of at least two permanent magnets of alternating polarity. The magnets are attached to a ferromagnetic back plate that has precision machined countersunk slots to accept the permanent magnets in such a manner that will allow for accurate pole pitch spacing along the magnetic array. The countersunk slots, surround and keep the highly attractive magnets in place; a one-piece non-ferromagnetic conductive material, ladder type, frame laminated to an identical one-piece conductive type frame and then welded into a non-magnetic case. The frames are blind drilled and tapped to match the bolt pattern of the ferromagnetic back plate.

[0006] In an embodiment, the invention provides a synchronous linear secondary stator member that is electrically synchronous which will accompany a primary member, the synchronous linear permanent magnet motor. The system of the present invention provides a variable stator electrical frequency as the primary permanent magnet synchronous motor enters the synchronous linear stator member at a particular velocity, wherein the electrical frequency along the synchronous linear stator member diminishes as vehicle velocity fades. The stator member has narrow slots which provide a pole pitch spacing that corresponds with the pole pitch spacing of the permanent magnet linear synchronous primary member. The slotting of the secondary stator causes the electrical currents in the stator to move through discrete pathways during transient dynamic excitation. The electrical frequency can be adjusted by increasing or decreasing the identical pole pitch spacing of both the primary and secondary members, thereby allowing a variable braking force throughout the entire active braking area.

BRIEF DESCRIPTION OF THE DETAILED DRAWINGS

[0007]FIG. 1 is a latitude cross section view of the assembly showing the ferromagnetic back plate with the machined countersunk magnet slots, the non-ferromagnetic conductive type frame with the o'ring seal groove, the conductive type material frame, the encapsulating case that welds to the frames, the magnet and the flat head countersunk non-magnetic bolts.

[0008]FIG. 2 is a longitudinal cross section view of the assembly, illustrating the magnet pole arrangement, the flux path circuit, the machined countersunk magnet slots and the perspective frames.

[0009]FIG. 3 illustrates a cutaway of the ferromagnetic back plate, the magnet, the bolt pattern, the non-ferromagnetic conductive frame and o'ring seal groove, the conductive frame and the encapsulating case that welds to the frames.

[0010]FIG. 4 illustrates the ferromagnetic back plate and the bolt pattern.

[0011]FIG. 5 illustrates a top view of the ferromagnetic back plate and the countersunk magnet retaining slots.

[0012]FIG. 6 illustrates the ferromagnetic back plate and frame and case as an assembly.

[0013]FIG. 7 is a three dimensional cutaway drawing showing the cast or extruded, machined one piece conductive type alloy frame/cover and the o'ring seal groove.

[0014]FIG. 8 illustrates the vertical X & Y axis view of the synchronous linear secondary stator member with narrow slots cut out at a 5-10 degree angle.

[0015]FIG. 9 illustrates the vertical X & Y axis view of the synchronous linear secondary stator member with narrow slots cut out at a 90 degree angle.

[0016]FIG. 10 illustrates a cutaway vertical X & Y axis view of the preferred embodiment of the braking system, which includes the primary synchronous linear permanent magnet motor and the synchronous linear secondary stator member.

[0017]FIG. 11 illustrates an enlarged vertical X & Y axis view of the one-piece synchronous linear secondary stator member having one enlarged narrow slot with a non-conductive insulating barrier around the inside edge of the slot, the highly permeable steel or ferrite core within the slot and the discrete synchronous current loop.

[0018]FIG. 13 top view illustration of the primary synchronous rotary motor showing a four pole alternating magnetic array and the ferrous magnetic back plate.

[0019]FIG. 14 shows a top view illustration of top view secondary synchronous rotary disk.

[0020]FIG. 15 shows a side view illustration of a shaft with a secondary synchronous stator disc splined in the center and the primary synchronous permanent magnet rotary motor on each side of the secondary member which is shown to being guided by a slide type mechanism.

[0021]FIG. 16 is a top view illustration of the machine one-piece highly conductive cover that bolts to the rotary ferromagnetic back plate.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

[0022] The device for surrounding, guiding and covering the permanent magnet array 1, comprises a frame 4, preferably made of stainless steel, which is laminated to another frame 5, preferably made of a conductive type element such as copper or aluminum or any other highly conductive material. The laminated frames 4, 5 are welded into a corrosive resistant, non-magnetic stainless steel case 6. The desired pole pitch spacing is determined by the dimensions of this double frame and cover 4, 5, 6. The frame is drilled and blind tapped 9 to accept the ferromagnetic back plate 2. The back plate 2 has a matching countersunk bolt pattern. The stainless steel portion of the frame 4 provides the surface that mates to the ferromagnetic back plate 2. This stainless steel surface 4 or the surface of the ferromagnetic back plate 2 contains an o'ring seal groove 7 precision machined around the entire perimeter and bolt holes to accept an o'ring seal 7 a, preferably made of rubber, to provide a watertight seal when the frame and cover 4, 5, 6 are bolted to the ferromagnetic back plate 2, due to the intolerance of the permanent magnets to aqueous and corrosive environments.

[0023] Two means are incorporated into the frames 4, 5 and ferromagnetic back plate 2 for ensuring the precise alignment of the permanent magnet array 1. The first is provided by the laminated frames 4, 5 and the second is provided by the ferromagnetic back plate 2. The depth or elevation of the frames 4, 5 are designed to match the elevation of the permanent magnet array 1, and the one-piece segmented double frame 4, 5 is dimensioned and machined to match the pole pitch of the magnet array 1. The pole pitch spacing between each individual magnet 1 will be identical to the spacing of segments of the one-piece double frame/cover 4, 5, 6. The back plate 2 contains precision machined pockets 3 to accept the permanent magnet array 1. The counter sunk pockets 3 are machined to a slight oversized dimension of the magnet 1. The magnets 1 are preferably attached by means of epoxy adhesive to the ferromagnetic back plate 2 within the countersunk pockets 3. The machined countersunk pockets 3 will not allow the magnets 1 to slide back and forth or attract one another, due to their alternating pole arrangement. Therefore, the magnet array 1 can be attached to the ferromagnetic back plate 2 so that the one-piece double frame/case 4, 5, 6 can be attached at any given time thereafter. The double frame/case 4, 5, 6 provides a protective barrier between the magnetic array 1 and other external influences such as water, salt mist, corrosive contamination, metal objects and dirt and debris.

[0024] The one-piece conductive frame 5 that is laminated to the one-piece stainless frame 4 will surround the upper portion of each magnet 1 such that the conductive frame 5 will enhance the flux field emitted by the permanent magnet array 1 by at least 5% or greater when introduced to a secondary stator portion. The conductive frame 5 will also reduce spatial harmonics that commonly occur during transient dynamic motion and high force application.

[0025] The above described double frame and stainless steel case 4, 5, 6 can also be cast as a one-piece alloy frame and case 11 or machined as such from a solid billet of extruded conductive material. The casting material utilized is a proprietary conductive type alloy. The one-piece cast design 11 acts as a case and frame. The frame 11 will consist of ladder type segments that will maintain the desired pole pitch spacing between each magnet 1. The elevation of the one-piece frame/case 11 will again be determined by the elevation of the permanent magnet array 1. The permanent magnet array 1 will consist of at least two or more permanent magnets with alternating polarity. This one-piece cast alloy frame 11 will also act as the shading or dampening frame to reduce spatial harmonics, flux leakage and flux fringing as previously mentioned by at least 5%. The surface of the frame 11 which mates to the ferromagnetic back plate 2 is precision machined with an o'ring seal groove 7 to accept an o'ring seal 7 a, preferably rubber, that may be the round or square type. The ferromagnetic back plate 2 again contains precision machined countersunk pockets 3 to accept the permanent magnet array 1. The countersunk slots 3 will be spaced accordingly to provide the desired pole pitch spacing between each magnet 1. Again, the cast alloy or extruded frame/cover 11 may be bolted to the ferromagnetic back plate 2 at any given time without damaging or altering the desired pole spacing between the permanent magnet array.

[0026] In an embodiment, the invention consists of a one-piece linear stator rail 25 constructed of at least one layer of conductive material such as brass, copper, aluminum, beryllium copper, titanium or any other highly conductive alloy or material. The above material can be laminated, one on top of the other, as illustrated in FIGS. 8 & 9. By laminating more than one conductive material, a variable electro-dynamic brake drag will occur along the secondary stator member 25 as a function of time wherein copper would provide (t1) aluminum (t2) brass (t3).

[0027]FIG. 8 shows narrow slots cut out at a 5-10 degree angle, the pole pitch spacing, the discrete synchronous current loop, the non-conductive barrier around the inside edge of the slot, the highly permeable steel or ferrite core within the slot and two one-piece dissimilar conductive layers, shown as (t1) aluminum and (t2) copper. FIG. 9 illustrates the vertical X & Y axis view of the synchronous linear secondary stator member. The illustration shows narrow slots cut out at a 90 degree angle, the pole pitch spacing, the discrete synchronous current loop, the non-conductive insulation barrier around the inside edge of the slot, the highly permeable steel or ferrite core within the slot and two one-piece dissimilar conductive layers, shown as (t1) copper and (t2) aluminum. FIG. 10 illustrates a cutaway vertical X & Y axis view of the preferred embodiment of the braking system, which includes the primary synchronous linear permanent magnet motor with a ferromagnetic back plate and eight alternating negative and positive magnets and the flux path return circuits that travel through the secondary member. The illustration also includes the double-layered synchronous linear secondary stator member showing a cutaway view of the narrow slots and how the pole pitch of the slots, match the pole pitch of the alternating permanent magnets. FIG. 11 illustrates an enlarged vertical X & Y axis view of the one-piece synchronous linear secondary stator member having one (enlarged for illustration) narrow slot with a non-conductive insulating barrier around the inside edge of the slot, the highly permeable steel or ferrite core within the slot and the discrete synchronous current loop.

[0028] The stator 25 has narrow slots cut out along the Y-axis at a pre-determined pole pitch 30. The narrow slots 31 provide at least two purposes. One purpose is to direct the electrical currents to run in a synchronized and discrete pathway 32 along the secondary stator 25 during transient dynamic motion as the synchronous linear permanent magnet motor enters said stator. The second purpose of the slotting is to allow for the installation of a small highly permeable steel or ferrite core 29, when use of such core is desired. However, ferrite core slot inserts are not required. In an embodiment, the steel or ferrite core 29 is surrounded by an electrical insulating type material 28 such as nylon 6/6, fiberglass G-10, fiberglass insulating tape or any other insulating type barrier. Therein the steel or ferrite core 29 will not touch the edges of the conductive stator rail 25 once installed. The insulated material 28 between the core and the conductive stator will prevent electrical shorts during excitation. The steel or ferrite core 29, as shown in FIGS. 8, 9 and 11, is utilized to maintain or increase the magnetic flux between the air gap of the double sided linear synchronous permanent magnet primary member 1 during high and low speed dynamic excitation. The narrow slots that are cut into the secondary stator member 25 along the Y-axis are slotted at about a 5 to 10 degree angle or eliminate brake pulsation along the active brake area. The narrow slots may also be slotted at a 90 degree angle along the active braking area as illustrated in FIG. 9. Narrow slots 31 create a higher electro-dynamic drag coefficient than the use of wide slots. In an example, the secondary synchronous linear stator member 25 does not consist of any other steel or ferrous material other than the highly permeable steel or ferrite core 29 that is utilized within the narrow slots 31. To reduce initial braking “jerk rate” as the moving vehicle enters the synchronous linear secondary member 25, a particular number of the highly permeable steel or ferrite cores 29 may be removed from the initial entry of the active braking area or left out all together as illustrated in FIGS. 8-11.

[0029] The primary member in an embodiment consists of a double sided linear synchronous motor consisting of at least two permanent magnets of negative and positive polarity situated on opposite sides of the secondary stator member (transverse axis) as illustrated in FIG. 10, for example. Magnets 44, 34, 35, 36 as illustrated in FIG. 10 are arranged so as to face positive and magnets 45, 37, 38, 39 are arranged so as to face negative. Wherein this arrangement allows a flux return circuit 26 to occur through the secondary stator member 25. Wherein FIG. 10 illustrates an eight pole permanent magnet configuration 1. Wherein the pole pitch 27 of the permanent magnet 1 along the transverse-axis will match the pole pitch 23 of the secondary synchronous stator member along the same transverse-axis, wherein a distinct synchronous electrical circuit path 32 will occur during transient excitation. The pole pitch of the synchronous primary permanent magnet member 27 and the secondary synchronous stator member 33 will depend on the entry velocity of the object or vehicle being stopped or slowed down. In other words, the electrical frequency of the secondary synchronous stator member 25 can be tuned to a particular frequency (Hertz) at vehicle entry by expressing,

Vs/2Tp=f.

[0030] Where Tp is the pole pitch of the linear synchronous permanent magnet member in meters and Vs is the entry velocity of the vehicle. f is the frequency produced in Hertz. As the braking force fades or decays, the electrical frequency along the linear secondary synchronous stator member 25 diminishes accordingly.

[0031] The primary synchronous permanent magnet member 1 may be affixed to the non-stationary vehicle or may be affixed in a stationary manner along the vehicle pathway. As well, the secondary synchronous stator member 20 may be affixed to the non-stationary vehicle or may be fixed in a stationary manner along the vehicle pathway.

[0032] The described synchronous linear permanent magnet braking device has also been designed so as to function in a rotational manner as well. This application would provide a means of energy dissipation by reducing kinetic energy along a rotating shaft, 20, gear assembly, axle or any other rotating device requiring the reduction or total decay of rotational movement.

[0033] The aforementioned linear primary synchronous permanent magnet motor will continue to be arranged so that the alternating positive and negative permanent magnet array will be affixed 360 degrees around a disc shaped ferromagnetic back plate, 1, where in an opposite array of permanent magnets, 4,5,17,14,15,18 face one another in an opposite polarity configuration. This configuration will consist of at least two permanent magnets of alternating polarity. The disc shaped ferromagnetic back plates, 1 will be affixed to a slide assembly, 21. This slide assembly, 21 will allow the opposing disc shaped synchronous permanent magnetic assemblies to remain aligned with one another along the transverse axis. The slides 21 will also allow transverse or perpendicular movement of each opposing back plate thereby allowing for an adjustable magnetic air gap. The disc shaped synchronous permanent magnet assemblies may be controlled and adjusted by means of an air or hydraulic cylinder(s), 22, linear actuators, manual pivoting lever or any other mechanical or electrical means to control or variate the width of the air gap, 24.

[0034] Between the magnetic air gap, 24 of the opposing synchronous permanent magnet array, 4,5,17,14,15,18 will be the secondary synchronous conductive disc, 2. Whereby this disc consists of a single layer or multiple layers of a conductive material. Wherein the multiple layers of conductive material will cause a variable electro-dynamic drag to occur as a function of time throughout the braking cycle. Wherein the synchronous secondary conductive disc, 2 will have slots, 11 cut through a portion of the Y-axis along the active braking area. To reduce braking pulsation during a brake cycle, the slots, 11 will be cut to at least a 1 degree angle, 360 degrees along the transverse axis of the aforementioned disc, 2.

[0035] The invention can also be configured to where the secondary synchronous conductive disc, 2 would be attached in a stationary manner to prevent rotation. The primary synchronous permanent magnet motor would be attached to and rotate with the rotating member. However, the rotating primary synchronous permanent magnet motor would continue to be designed to slide or actuate in a variable manner transversely or perpendicular to the fixed synchronous secondary disc, 2 as illustrated in FIG. 3.

[0036] The ferromagnetic back plate, 1 of the primary synchronous permanent magnet motor and the hermetically sealed conductive cover that attaches to the ferromagnetic back plate, 1 will be constructed according to the linear version. 

What is claimed is:
 1. A synchronous linear electrical machine operating as a motor or an electrodynamic brake consisting of an array of at least two permanent magnets 1 of alternating polarity; the magnets 1, being attached to a ferromagnetic back plate 2, that has precision machined countersunk slots 3, to accept the permanent magnets 1, in such a manner that will allow for highly accurate pole pitch, spacing along the magnetic array
 1. The countersunk slots 3, surround and keep the highly attractive magnets 1 in place; a one-piece non-ferromagnetic conductive material, ladder type, frame 4 laminated to an identical one-piece conductive type frame 5 and then welded into a non-magnetic, case
 6. The frames 4,5 being blind drilled and tapped to match the bolt pattern 10 of the ferromagnetic back plate
 2. Secondary synchronous stator member.
 2. The synchronous linear motor of claim 1, wherein the ferromagnetic back plate 2 is the structural or electrical type steel which has precision machined countersunk slots 3, to accept the permanent magnet array 1, at a pre-determined pole pitch spacing, without the use of guide pins or individual raised non-magnetic spacers.
 3. The synchronous linear motor of claim 1, wherein the double one-piece non-magnetic, frame 4, which is laminated to an identical one-piece conductive type frame 5 and is then welded into a non-magnetic case
 6. The ladder spacers that are parallel to the permanent magnet array 1, provide additional, precise pole pitch alignment and provide secondary protection between each permanent magnet
 1. 4. The synchronous linear motor of claim 1, wherein the one-piece conductive ladder type frame 5, which is laminated to the one-piece non-ferromagnetic conductive material, ladder type, frame 4, acts as a spatial harmonic dampening device, which surrounds and shades the upper portion of each permanent magnet 1, thereby reducing spatial harmonics, leakage flux and flux fringing by at least 5%.
 5. The synchronous linear motor of claim 3, wherein there is an o'ring groove 7 precision machined into the mating surface of the one-piece non-ferromagnetic conductive material, ladder type, frame 4 or the mating surface of the ferromagnetic back plate
 2. The o'ring groove 7 is machined near the outside leading edge of this surface area and bolt holes and will accept a one-piece round or a one-piece square o'ring type rubber seal 7 a.
 6. The synchronous linear motor of claim 3, wherein the one-piece double non-ferromagnetic conductive material and conductive, ladder type, frames 4,5 are substituted by a cast one-piece conductive alloy frame and cover 11 or machined as such from a solid billet or extruded conductive material. This ladder type frame 11 provides precision parallel pole pitch alignment along the magnetic array
 1. 7. The synchronous linear motor of claim 6, wherein the one-piece conductive cast alloy frame 11 will act as a damper circuit, which when attached to the ferromagnetic back plate 2, will surround and shade the outside and upper portion of each permanent magnet 1 within the array 1, thereby reducing spatial harmonics, leakage flux and flux fringing by at least 5%. A further benefit of the frame is to increase the magnetomotive force of each pole during transient mechanical motions, to enhance the air gap magnetic field density and increase dynamic braking thrust.
 8. The synchronous linear motor of claim 6, wherein there is an o'ring groove 7 precision machined into the mating surface of the cast one-piece conductive alloy frame 11 or the mating surface of the ferromagnetic back plate
 2. The o'ring seal groove 7 is machined near the outside leading edge and around the bolt holes of these surfaces and will accept a one-piece round or a one-piece square o'ring type rubber seal 7 a, which will provide a watertight seal when the assembly is bolted together. The seal will eliminate contamination that may otherwise be harmful or damaging to the permanent magnetic material, due to intolerance to aqueous and corrosive environments.
 9. The synchronous linear motor of claim 2, wherein the ferromagnetic back plate 2 has a uniquely designed bolt pattern 10 which utilizes countersunk non-magnetic flat head or socket cap bolts 8 to fasten said ferromagnetic back plate 2, to the corresponding frame/cover 4,5,6 or the one-piece cast alloy extruded frame/cover
 11. The unique countersunk bolt pattern 11 surrounds each permanent magnet 1 and affixes the one-piece non-ferromagnetic conductive frame and conductive frame/case 4,5,6 or the one-piece cast alloy frame/case 11 in such a manner, that will reduce or eliminate twisting and shifting of the magnet array 1, under high force applications. By reducing or eliminating twist, the outside surface of the non-magnetic case 6 or the outside surface of the one-piece alloy frame/case 11 will maintain a highly accurate and constant air gap between the linear synchronous motor as an assembly 12 and a secondary electrical member.
 10. A one-piece synchronous linear secondary stator member, or rail, and a primary double sided synchronous linear permanent magnet electrical machine operating as a motor or electro-dynamic brake consisting of at least two permanent magnets of positive and negative polarity, wherein the double-sided primary synchronous permanent magnet motor maybe affixed stationary to a moving vehicle pathway. As well, the one-piece secondary synchronous linear stator member may be affixed stationary to a moving vehicle or may be affixed in a stationary manner along the vehicle pathway.
 11. The system as described in claim 10 wherein the synchronous linear stator member is a one-piece non-layered or multi-layered conductive rail, wherein said rail is slotted at a 90 degree angle at a pre-determined pole pitch spacing, thereby causing a discrete synchronous current path around said slots during transient dynamic motion, wherein laminating more than one conductive material, a variable electro-dynamic brake drag will occur along the synchronous linear secondary stator member as a function of time.
 12. The system as described in claim 10 wherein the synchronous linear stator member is a one-piece non-layered or multi-layered conductive rail, wherein said rail is slotted to at least a 1 degree angle at a pre-determined pole pitch spacing, thereby causing a discrete synchronous current path around said slots during transient dynamic motion, wherein laminating more than one conductive material, a variable electro-dynamic brake drag will occur along the synchronous linear secondary stator member as a function of time. Where in by angling the slots at least 1 degree along the secondary synchronous stator member, a reduction of brake pulsation will occur along the synchronous linear secondary stator member, otherwise known as the active braking area.
 13. The system as described in claims 10 and 11 wherein the slots contain a non-conductive insulating barrier around the inside edge of said slot and wherein the center of said slot contains a highly permeable steel or ferrite core, thereby said core will boost or sustain the magnetic flux density within the air gap of the double sided primary synchronous linear permanent magnet motor during rapid and decaying transient dynamic motion.
 14. The system as described in claim 13 wherein the said slots may not contain the highly permeable steel or ferrite core at particular intervals, thereby reducing initial braking “jerk rate” as the moving vehicle, with the affixed double-sided synchronous linear permanent magnet motor, enters the synchronous linear secondary stator member.
 15. The system as described in claims 10 and 11 wherein the pole pitch spacing of the slots along the synchronous linear secondary stator member matches the, negative and positive alternating magnet, pole pitch spacing of the synchronous linear double-sided permanent magnet motor, thereby causing a discrete synchronous electrical current and frequency to occur along the said secondary stator member.
 16. The system as described in claim 15 wherein by increasing and decreasing the length of said pole pitch spacing of the primary synchronous linear permanent magnet motor magnets and the synchronous linear secondary stator member slots will allow said system to be tuned to a particular electrical frequency upon the initial entry of the vehicle or object into the active braking area. Thereby, as the velocity of the vehicle diminishes or fades, the electrical frequency decreases along the active braking area causing a variable frequency braking effect. 